1. Field of the Invention
The present invention relates to a hermetically sealed compressor used for refrigeration and air-conditioning, and particularly to a technique of enhancing COP (Coefficient Of Performance: refrigeration power/input power) of a hermetically sealed compressor.
2. Description of the Related Art
There is known a hermetically sealed rotary compressor including an electrically-driven element and a rotary compression element driven by the electrically-driven element to compress refrigerant that are accommodated in a hermetically sealed container. This type of hermetically sealed rotary compressor is disclosed in JP-A-6-323276, for example. According to this hermetically sealed rotary compressor, an eccentrically rotating roller is disposed in a cylinder so as to keep predetermined clearance from the inner surface of the cylinder and form a crescent-shaped space (so-called compression chamber) in the cylinder. Furthermore, a vane is provided so as to come into sliding contact with the roller, and the crescent-shaped space is partitioned to a refrigerant-sucking low-pressure chamber side and a refrigerant-compressing high pressure chamber side by the vane in terms of pressure.
However, the conventional hermetically sealed rotary compressor has a problem that the sealing performance of the crescent-shaped space is not sufficient, resulting in reduction of the cooling efficiency of the hermetically sealed rotary compressor.